-- Video On Demand -- - Introduction - Video on Demand (VoD) is an interactive multimedia system that works like cable Television, the difference being that the customer can select a movie from a large video database. Individual customers in an area are able to watch different programmes when they wish to, making the system a realisation of the video rental shop brought into the home. As the underlying technologies are relatively new, Video on Demand still lacks a universal standardisation. Nevertheless, many research institutes and commercial organisations have established de-facto standards and consequently, there are many operational VoD-related services available today. Some of the key areas of today's VoD-related applications are : ·Providing Video Films on Demand ·Local News and Weather Forecasting ·Games, Music and Leisure ·Education and Remote Learning Facilities ·Home Shopping and Other Consumer Services ·Banking
Almost every home has a television today. It offers programmes from a number of available channels and is very simple to use. The Cable TV (CATV) makes it possible to choose programmes from large number of channels. Then became video rental business in combination with a video recorder, which provides customers to select movies when they will. This service may be called video on demand. Nowadays Video-on-Demand (VoD) includes much wider services and opportunities. Todays technology allows telecommunication network operators to offer such services as home shopping, games, and movies on demand. These services should have a competitive price comparing to the video rental, and customers do not need to travel for the services. These possibilities have been reached by the development of the telecommunication and electronic industry. The capacity of a hard disk has doubled almost every year at near-constant cost. The useful compression ratio for video has been increased considerably, MPEG-formatted video can be transported at a bit rate of few Mbit/s. The digital signal processing techniques permit the transport of a few Mbit/s over existing copper wires for a distance of a few kilometres. Finally, Asynchronous Transfer Mode (ATM) systems allow the switching of any reasonable bit rate to a single or multiple customers among a large number of connected customers. However, todays transmission bandwidth is large only downstream towards the customer with narrow upstream bandwidth. But upstream bandwidth will also become wider in the future, then interactivity between the customer and the service provider will increase.
This new technology is being developed all the time, because Video-on-Demand has so many different applications to offer to the customers and economical possibilities have been seen. Many companies, organisations and universities are developing products and standards. Both cable TV and telephone operators invest to their networks and have some trials in Video-on-Demand. To finance the required investments, higher consumer volumes must be reached from residential side instead of business side that is running ahead in the development of technology. The battle is hard, and it is getting harder all the time. So some companies have established business relationships to get their knowledge and resources together. In addition, they may avoid some regulation restrictions before telecommunication markets are opened to everyone.
- How Video On Demand works - When a subscriber requests a movie from the VOD system, the ultimate result is that a compressed digital stream of bits representing the movie is transmitted from the video server to the set top box (STB), where it is decoded back to good old analog video and audio, and displayed on the TV directly or by being modulated on an RF channel that links the TV to the set top box. However, there are a few steps involved to cause this to happen : · First, the movie has to be digitized and compressed, and distributed to the video server.
· Information about the movie has to be added both to the management system (e.g. during what period does our contract with the studio allow us to play the movie), and to the list of movies from which the customer makes a selection (e.g. title, stars, cost, etc.). · When the customer selects the VOD “channel” on the STB, video provider have to make sure that the application that displays the VOD information is loaded on the STB. · When the customer chooses a movie, video provider have to make sure that there are no account problems that would make it a poor business decision to deliver the movie, and that video provider have enough bandwidth at this moment to deliver it. · Then video provider have to allocate the resources for the delivery, and set up the protection scheme which allows only that subscriber to view the movie. · Now video provider can start delivering the movie. However, video provider have to keep listening to the user in case they want to pause, fast forward, rewind, or stop the movie. · And if they don’t finish the movie, video provider need to keep it on a list of movies that that subscriber is entitled to continue to view during the period for which it was purchased. So that is why system diagrams look so complicated for an apparently simple job. Adding to the apparent complexity is the need for many separate computers. However, this is just because no individual processor is fast enough for all of the jobs video provider need to accomplish, so the jobs get subdivided and placed on different machines to speed things up. Also, video provider don’t want to put all of their eggs in one basket, so having more than one machine lets they continue to operate even if a machine fails. An important note about the word “server”: Server can mean a physical box running one or more processes, or it can refer to a software process itself. Or in the case of the video server, it can refer to a collection of boxes running as one entity! So always feel free to ask for clarification about computer terms. Remember, computer guys are the ones who think that 1K is 1024, and can’t decide if 1 M is 1,000,000 or 1024 x 1024! (Actually, technoids think it is 1024 x 1024, and marketers for hard drives think it is 1,000,000 because it makes the drive seem larger).
- Introduction -
Video on Demand (VoD) is an interactive multimedia system that works like cable Television, the difference being that the customer can select a movie from a large video database. Individual customers in an area are able to watch different programmes when they wish to, making the system a realisation of the video rental shop brought into the home.
As the underlying technologies are relatively new, Video on Demand still lacks a universal standardisation. Nevertheless, many research institutes and commercial organisations have established de-facto standards and consequently, there are many operational VoD-related services available today. Some of the key areas of today's VoD-related applications are :
· Providing Video Films on Demand
· Local News and Weather Forecasting
· Games, Music and Leisure
· Education and Remote Learning Facilities
· Home Shopping and Other Consumer Services
· Banking
Almost every home has a television today. It offers programmes from a number of available channels and is very simple to use. The Cable TV (CATV) makes it possible to choose programmes from large number of channels. Then became video rental business in combination with a video recorder, which provides customers to select movies when they will. This service may be called video on demand.
Nowadays Video-on-Demand (VoD) includes much wider services and opportunities. Todays technology allows telecommunication network operators to offer such services as home shopping, games, and movies on demand. These services should have a competitive price comparing to the video rental, and customers do not need to travel for the services. These possibilities have been reached by the development of the telecommunication and electronic industry. The capacity of a hard disk has doubled almost every year at near-constant cost. The useful compression ratio for video has been increased considerably, MPEG-formatted video can be transported at a bit rate of few Mbit/s. The digital signal processing techniques permit the transport of a few Mbit/s over existing copper wires for a distance of a few kilometres. Finally, Asynchronous Transfer Mode (ATM) systems allow the switching of any reasonable bit rate to a single or multiple customers among a large number of connected customers. However, todays transmission bandwidth is large only downstream towards the customer with narrow upstream bandwidth. But upstream bandwidth will also become wider in the future, then interactivity between the customer and the service provider will increase.
This new technology is being developed all the time, because Video-on-Demand has so many different applications to offer to the customers and economical possibilities have been seen. Many companies, organisations and universities are developing products and standards. Both cable TV and telephone operators invest to their networks and have some trials in Video-on-Demand. To finance the required investments, higher consumer volumes must be reached from residential side instead of business side that is running ahead in the development of technology. The battle is hard, and it is getting harder all the time. So some companies have established business relationships to get their knowledge and resources together. In addition, they may avoid some regulation restrictions before telecommunication markets are opened to everyone.
- How Video On Demand works -
When a subscriber requests a movie from the VOD system, the ultimate result is that a compressed digital stream of bits representing the movie is transmitted from the video server to the set top box (STB), where it is decoded back to good old analog video and audio, and displayed on the TV directly or by being modulated on an RF channel that links the TV to the set top box.
However, there are a few steps involved to cause this to happen :
· First, the movie has to be digitized and compressed, and distributed to the video server.
· Information about the movie has to be added both to the management system (e.g. during what period does our contract with the studio allow us to play the movie), and to the list of movies from which the customer makes a selection (e.g. title, stars, cost, etc.).
· When the customer selects the VOD “channel” on the STB, video provider have to make sure that the application that displays the VOD information is loaded on the STB.
· When the customer chooses a movie, video provider have to make sure that there are no account problems that would make it a poor business decision to deliver the movie, and that video provider have enough bandwidth at this moment to deliver it.
· Then video provider have to allocate the resources for the delivery, and set up the protection scheme which allows only that subscriber to view the movie.
· Now video provider can start delivering the movie. However, video provider have to keep listening to the user in case they want to pause, fast forward, rewind, or stop the movie.
· And if they don’t finish the movie, video provider need to keep it on a list of movies that that subscriber is entitled to continue to view during the period for which it was purchased.
So that is why system diagrams look so complicated for an apparently simple job. Adding to the apparent complexity is the need for many separate computers. However, this is just because no individual processor is fast enough for all of the jobs video provider need to accomplish, so the jobs get subdivided and placed on different machines to speed things up. Also, video provider don’t want to put all of their eggs in one basket, so having more than one machine lets they continue to operate even if a machine fails.
An important note about the word “server”: Server can mean a physical box running one or more processes, or it can refer to a software process itself. Or in the case of the video server, it can refer to a collection of boxes running as one entity! So always feel free to ask for clarification about computer terms. Remember, computer guys are the ones who think that 1K is 1024, and can’t decide if 1 M is 1,000,000 or 1024 x 1024! (Actually, technoids think it is 1024 x 1024, and marketers for hard drives think it is 1,000,000 because it makes the drive seem larger).
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